Piston packing ring



192 Aug 7 c. c. FARMER PISTON PACKING RING Filed Sept. 30, 1926' I Ill INVENTOR W Y M M R .R Wm c T A. E m cs Patented Aug. 30, 1927.

' UNITED STATES PATENT OFFICE.

CLYDE C. EARLIER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A COB-POBATION OI. PENNSYLVANIA.

PISTON PACKING RING.

Application filed September 30, 1926. Serial No. 138,616.

This invention relates to packing, and more particularly to a piston packlng ring.

It is common practice to make plston packing rings with the inner peripher eccentr c to the outer periphery so that t e r1ug 1s thickest at the point opposite the spht )Olllt of the ring and gradually reduces in thickness to the joint, where the ring is the thlnnest, the purpose being to ensure substantially uniform outward pressure of the ring against the cylinder wall throughout the circumference of the ring and thereby substantially uniform wear of the ring.

A piston ring should be fitted very accurately in the piston ring groove of the piston,

in order to minimize leakage, but any increase in the width of the bearing faces of the ring engaging the side walls of the groovetends to increase the frictional resistance to lateral movement of the ring and thereby increases the liability of the ring sticking, thus tending to cause the ring to hear so unevenly a ainst the cylinder wall, so as to permit lea age at some portion of the ring.

In addition, excessive depth of the side bearing of the ringincreases the dilficulty of assembling the ring in the piston groove and the liability to permanently distort it during side bearing increases the length of the ring subjected to deflection while slipping the ring over the piston and therefore reduces the liability to distortion.

Furthermore, it is practically impossible to cut the iston ring groove in the piston so that the sides of the groove are para lel, with the result that if the ring has groove bearing faces which are wider at one point than at another, and if the ring is ground so as ,to apparently fit into thegroove, the groove may then be wide enough where the ring has the shallower bearing faces, so that leakage will occur.

' It istherefore highly desirable to provide bearing faces on the mug of uniform width so that the frictional resistance to lateral movement in the groove will be uniform throughoutthe circumference of the ring, and for this purpose, eccentric rings of the above character have heretofore been made with the thickened portion of the ring slight- 1y tapered inwardly, so as to leave a groove assembly, while, on the other hand, a shallow bearing face at each side of the ring of uniform width. It is difficult to so accurately machine this taper as to ensure uniform bearing faces, and to do so is considered commercially impracticable. In addition, in order to ensure an accurate fit in the groove, the rings are lapped to a fit and this lap ing. further tends to cause variation in the wldth of the groove bearing faces.

The taper further forms a wedge shaped pocket, in which dirt and dust may collect and then readil work its way between the bearing faces 0 the ring and the side walls of. the iston groove in which :the ring is mounted v and consequent leakage.

There is also a certain desirable type of piston ring joint, in which leakage past the oint at one portion is prevented only by a narrow face which is so positioned at the inner edge of the rin that when the ta r is machined on the ring, if not extreme y accurate, will oftentimes be such that the taper will extend past the-narrow face above referred and thus permit leakage.

and thus cause scoring of the ring The principal object of my invention is to provide a piston ring of the above character, in which uniform'bearing faces on the ring are assured.

In the accompanying drawing; Fig. 1 is a face view of a piston packing ring constructed in accordance with m invention;

and Fig. 2 a section on the ine 2 2 of Fig.1.

The packing ring 1, as shown in the drawing, is made thickest at the point opposite the ring joint, the thickness of the ring gradually diminishing, so that the ring is eccentric or crescent shaped. The joint may be effected by providing one free egd of the ring with a tongue 2 having a beveled face adapted. to engage a corresponding beveled face provided at the other free end of the ring.

Accordin to my invention, instead of beveling '0 that part of the ring which is thickened, the ring is counterboredron its opposite sides at 3 and 4, so that the bearing faces 5 and 6- of the ring are of uniform width, as indicated in Fig. 1. With the faces of the ring counterbored, it will be evident that the faces of the ring may be lapped'as desired, in order to fit the ring homing;

iii the piston groove, Without diStU1'i3it1I or changing the iihitorinity ot the hearing qrw we;

i is also to he noted their with the type or spiit joint shown here there is a narrow face '2' at one side ot the ring, saint hmr' 1g time will otwoye he maintained with the ring; coiihterhoreci iii ELCCOTLttEtTIQB With my i htioh whereee with the ring; tapered, the taper is iiohie Lo extenti 1e portion. 'i and thus d em the ioaitrrigotriees ot the int oi; that tacit;

Wing" now iieecrihed h. it etnim how itiltt desire iteiih is:

c iit piston pitching ring of invention, What secure toy h grechiei- ,5 iricro n r 'ritith trom the joint to the i oppmite the joint, L ring; heihg iiiterhoreiit at its opposite it to leave tacos of iiiiitorih Wititil throughout mice of the rim",

gistoh pitching rreg of graduatihored feces being" pareilet with eiiici hearing "feces.

3. it spiit piston packing ring having the inner periphery eccentric to the outer periphery and having" the eccentricity at the opposite feces counterhored, leaving hearing iiacee having concentric peripheries.

i. Eixsplit piston packing ring having its inner peri iihery eccentric to its outer pe riphery and having; its groove bearing faces counterhoreit so thatthe shoulder of the counterhore is concentric with the outer periphery oi the ring.

in testimony whereof it have heremito set my hand.

CLYDE C. FARR KER. 

